Telephone subscribers appts. signalling test procedure - using exchange registers to test signalling conditions from telephone dial or multifrequency sender

A test programme is run in a stored programme control telephone exchange, esp. a p.b.x., in order to test the dial pulse or multi-frequency number output of the telephone subscriber's appts. The exchange comprises subs line terminating units (TS1...TSn) connected both to the switch block (KN) and the central common control and stores (St,ZSt). Also connected to the switch block are registers for receiving loop disconnect dialled pulses (WAS) and multi-frequency signals (IS) from the telephone or incoming trunks. By dialling a predetermined code the subscriber's appts. (T1... Tn) can be connected through to the appropriate register (WAS or IS) in a test mode by the common control (St,ZSt). Dialled or multi-frequency transmitted signals are verified by the equipment by transmitting audible tones back to the subscriber's appts.